To establish the long-term effects of raloxifene, a phase III, multi-center, double-blind, placebo-controlled, randomized trial at two doses (60 or 120 mg) will be conducted in 36 postmenopausal women with low bone mineral density or thoracic or lumbar vertebral compression fracture. The primary endpoint is the rate of vertebral fractures in raloxifene-treated vs. placebo controls.